US2527061A - Electric control unit - Google Patents

Description

O ct. 24, 1950 R. A. HAIGH 2,527,061

ELECTRIC CONTROL UNIT Filed Oct. 14, 1947 PIU/ARD A. f/n/GH Patented Oct. 24, 1950 ELECTRIC CONTROL UNIT Richard A. Haigh, Brighton, Mich., assignor to Automatic Controls Corporation, Ann Arbor, Mich., a corporation of Michigan Application October 14, 1947, Serial No. 779,745

Claims.

This invention relates to improvements in electric control units, more particularly units adapted for either making or breaking an electric circuit for a certain length of time once during a predetermined period of time, as for example a day of twenty-four hours. One eld of use is in thedefrosting of electric refrigerators.

One of the objects of the invention is the provision of apparatus for the purpose stated which shall be rugged, operable in any position, simple and consequently of low cost.

Another object is 'the provision of a novel means for actuating the control switch from the rotating hour shaft of a clock mechanism.

A further object is the provision of means for mounting the several parts of the mechanism simply, rigidly and compactly upon a wall of the casing of a unit which may be plugged directly in a wall for floor socket or receptacle.

Still another object is the provision of means for quickly and easily setting the clock mechanism to correspond with the time of day when it is put in operation and for selecting the time of day when the switch shall be actuated.

Other objects and features of novelty will appear as I proceed with the description of that embodiment of the invention which, for the purposes of the present application, I have illustrated in the accompanying drawing, in which Fig. l is a side view of a unit embodying the invention.

Fig. 2 is a front View thereof.

Fig. 3 is a longitudinal sectional view taken substantially on the line 3-3 of Fig. 4.

Fig. 4 is a transverse sectional View taken substantially along the line 4-4 of Fig. 3 showing the switch actuating mechanism in inoperative position.

Fig. 5 is a fragmental view similar to Fig. 4 showing the switch actuating mechanism in operative position, and

Fig. 6 is a detail sectional View on a larger scale, the view being taken substantially along the line 6 6 of Fig. 3.

In the drawing there is shown a casing of insulating material comprising a flat wall or base III and a cover I I which may include a cylindrical side wall and an end Wall integral therewith. rlhe cover may be secured to the fiat wall I0 by screws I2 which extend through the flat wall and are threaded into tapped openings I3 formed in bosses I4 on the inner side of the cover.

The unit embodies a clock mechanism. For obvious reasons a clock driven by a synchronous electric motor is preferred. Such a clock is illus- Lll) ,Fig 3.

2 trated herein but not in deail. It comprises a field magnet I5 which is attached by suitable means to bosses I6 on the casing wall I0. motor rotor and the clock gearing are enclosed in a housing I6 carried by the magnet I5. The magnet winding is indicated at I'I.

A sheet metal bracket I8 of brass preferably is carried by the magnet I5, being supported thereupon by screws I9 and 20 threaded kinto the respective ends of a pair of spacing columns 2i. The hour shaft 22 of the clock mechanism extends through an opening in this bracket. Rigidly mounted on the bracket parallel with the motor shaft 22 there is a post 23 upon which is rotatably and slidably mounted a hollow shaft 24 carrying at its lower or inner end a wheel 25. The upper portion of hollow shaft 24 is counterbored. Post 23 is bored and tapped to receive a screw 26 the head of which forms a stop r2'I for engagement with the shoulder in the shaft formed at the base of the counterbore. A coil spring 28 biases the hollow shaft 24 upwardly and holds it against the stop 21. Hollow shaft 24 extends upwardly through a hole 29 in the flat end wall of the casing cover, as shownin On its outer extremity there is mounted a handle pointer 30 which may be adjusted angularly to any desired position after a setscrew 3I is loosened.

In the periphery of wheel 25 there are a series of pockets or notches 32 which have circular contours. These notches are adapted to be engaged by a round headed lug 33 fixed in the hour shaft 22 of the clock mechanism. Preferably this lug is in the form of a pin which is press fitted into a transverse hole in the shaft. As it turns in the direction indicated by the arows in Figs. 4 and 5 it engages a notch as indicated in Fig. 4 and advances the wheel a distance corresponding to the spacing of the notches. In they illustrated example there are twenty-four notches 32, and hence the wheel 25 makes one complete revolution every twenty-four hours. Through a considerable part of each revolution of the hour shaft 22 the lug 33 is out of engagement with the wheel 25, and it is necessary at such times to hold the Wheel against rotation. This I accomplish by use of a spring detent 35 mounted on the bracket I8 having av curved extremity adapted to ride into and out of the notches 32 as the wheel turns. The mechanism illustrated for driving hollow shaft 24v will be referred to hereinafter as a Geneva motion mechanism.

On the bracket I8 I also mount an electric switch, preferably a microswitch of knownform Thev ' normal position.

contained in a switch housing 3@ and having a plunger 3l. A mounting screw 3S extends through housing 36 and is threaded into a tapped hole in the bracket I8. A second threaded fastening 39 extends through the housing 33 and into an arcuate slot 4U in bracket I8, see Fig. 4. By this means I am enabled to provide limited adjustment or". the microswitch by loosening the fastening 39 and tightening it again when the adjustment is accomplished.

The microswitch includes a leaf spring actuator 4l having the normal position illustrated in Fig. 4 and adapted to operate the plunger. 3l as it is swung down to or away from the position of Fig. 5. This actuator is moved by an abutment 42 attached to wheel 25 and thus turns in a circular path. As this abutment travels through the lower part of its orbit it wipes against the spring 4|, moving the latter first to switch actuating position and then away from. that position, nally leaving the spring and permitting the switch plunger 31 to again rise to its The length of time during which the switch is in actuated position may be varied to some extent by changing the length of the spring 4|. As is well understood in the art, switches of this type may be set either to make or to break a circuit when the switch is actuated.

In the wall ill of the casing are mounted two bus bars 44 and 45 which carry prongs fifi and 41 extending through the wall lf3 and adapted to be received in a wall or floor receptacle. They are spaced from the center of wall I5 so that when they are inserted in a` wall receptacle the center of gravity of the unit tends to swing it inward toward the Wall in which the receptacle is mounted.

Bracket I8V has a downturned lip 43 from which is supported a receptacle or plug socket 49 by suitable means including a screw 5D. This receptacle extends laterally away from the motor through an opening 5l in the side wall ii of the cover. Preferably this receptacle is provided with a flange 52 which overlaps opening 5i on three sides and thus helps to tie together the bracket I8 and the cover of the casing. In order to close the opening 5l below receptacle the base or at wall l0 of the casing is provided with an upstanding arcuate portion 53 which is ush with the cover wall when the parts are assembled and which stands just beneath and may abut the receptacle 4S.

Bus bar 45 is connected with a conductor which leads to one terminal or" the microswitch, From the other terminal thereof a conductor 53 leads to one terminal of receptacle 4t, and from the other terminal of that receptacle a conductor 51 extends back to the other bus -bar 44. The circuit for the receptacle 49 therefore includes and is controlled by thev microswitch. The clock motor of course may take its current also from the bus bars 44 and 45 by suitable connections, not shown.

Surrounding the hollow shaft 24 on the outside of the casing end wall there is a dial 88 marked with divisions equal to the number of notches 32. In the illustrated case there are twenty-four divisions comprising two series of divisions each numbered l to l2 inclusive, one series being marked Night and the other being marked Day. Preferably this dial is imprinted upon a separate plate of insulation Si which is secured to the casing by screws E2 or the like. In the normal position of the hollow shaft. 24 a space 63 is left between the handle pointer 3i) and the top of plate 6|.

Operation. When the unit is to be installed, for example in the line supplying power to a refrigerator, the operator first makes sure that the wheel 25 is in the position at which the actuation of the switch begins to take place. This may be accomplished by plugging the unit into a house receptacle convenient to the refrigerator, connecting a testing line to the receptacle 49, and turning the handle clockwise until the current in the testing line goes oif. This corresponds to the -beginning of the defrosting period. The operator then loosens setscrew 3| and turns the handle pointer 30 to point to the dial indication of the time of day or night at which the user desires to have the defrosting period commence, after which the operator tightens screw 3| in order to hold the handle pointer against rotation relative to hollow shaft 24. Next the operator presses down on the handle Sil, which depresses theV wheel 25, forcing it out of engagement with the lug 33. With the handle thus depressed the operator turns it untilV it points to the dial indication corresponding to the then correct time of day or night, when he releases the handle enabling the spring 28 to return the wheel 25 to engagement with the driving lug 33. He then removes the test line and puts the plug on the end of the refrigerator cord into the receptacle 4S of the unit. Current is thereby supplied to the refrigerator as needed, and the clock motor is started. The clock shaft 22 turns once each hour and during a certain portion of each revolution it advances the wheel 25 one notch. When the abutment 42 wipes over the leaf spring actuator 4I it actuates the microswitch to open the refrigerator circuit, which remains open long enough to defrost the refrigerator coils, alter which the abutment 42 leaves the actuator 4i and the latter springs back to its Fig. 4 position again establishing the refrigerator circuit. A small Variation in the period of actuation of the switch may be accomplished by loosening the fastening 39 and moving the switch housing through a small angle about the clamping screw 38.

In the foregoing description I have necessarily gone somewhat into detail in order to explain fully the particular embodiment of the invention herein illustrated, but I desire it to be understood that such details of disclosure are not to be construed as amounting to limitations, except as they may be included in the appended claims.

Having thus described my invention, I claim:

1. In an electric control unit, a casing, a clock therein having an hour shaft, a second shaft parallel to said hour shaft and projecting through said casing, Geneva motion mechanism comprising a lug on said hour shaft and a wheel on said second shaft provided with notches adapted to cooperate with Said lug for rotating said wheel once every twenty-four hours, an electric switch, means comprising an abutment turning with said second shaft for actuating said switch, a twentyfour hour dial on the outer side of said Icasing surrounding said second shaft, a pointer adapted to be secured in any angularly selected position on said second shaft exteriorly of the casing, said second shaft being movable lengthvise to shift said wheel out of the plane of said lug, whereby with the abutment in switch actuating position the pointer may be adjusted on the second shaft to indicate on the dial the time of day selected for switch actuation, after which the pointer and second shaft may be shifted lengthwise momentarily and adjusted angularly to indicate upon the dial the time of day at which the controller is put in operation.

2. In an electric control unit, a casing comprising a fiat wall and a cover, a synchronous motor attached to said flat wall, a bracket rigidly supported upon said wall, said motor having an hour shaft extending through an opening in said bracket, a post fixed in said bracket parallel with said motor shaft, a hollow shaft rotatable upon said post, a wheel on said hollow shaft, a Geneva motion connection between said motor shaft and said wheel for turning the latter once every twenty-four hours, a pair of metal prongs fixed in and projecting from said flat wall, an electric switch mounted on said bracket, an abutment on said wheel adapted to operate said switch, a plug socket fixed with respect to said bracket and flat wall and extending 4laterally of said motor and an electric circuit including said prongs, said switch, and the terminals of said socket, said cover having an opening therethrough to accommodate said hollow shaft'and another opening to expose the surface of said socket.

3. In an electric control unit, a bracket, a clock xed with respect to said bracket having a rotating hour shaft, a second shaft parallel to said clock shaft, Geneva motion mechanism for rotating said second shaft from said clock shaft, a support pivotally mounted at one end upon said bracket, an electric switch on said support, a leaf spring actuator carried by said support, an adjustable connection between said bracket and the opposite end of said support permitting the support to be swung on its pivot toward and away from said second shaft, an abutment turning with said second shaft contacting said spring actuator once for each revolution of said second shaft, whereby adjustment of said support on its pivot moves said actuator toward or away from the circular path of movement of said abutment to vary the length of time during which said abutment and spring actuator are in contact.

4. In an electric control unit, a casing, a clock mounted therein having a rotating hour shaft, a second shaft parallel to sai-d clock shaft extending through an opening in the casing, a time dial fixed on the casing surrounding said shaft, Geneva motion mechanism comprising a projection of said clock shaft, and a wheel on said second shaft, said wheel having a plurality of evenly spaced peripheral notches adapted to cooperate with said projection for rotating the second shaft, an electric circuit, a switch therein biased toward closed position, means comprising an abutment turning with said second shaft for opening said switch temporarily, said second shaft being slidable lengthwise to shift said wheel out of the plane of said lug, and a pointer on the outer end of said second shaft adapted to be secured in any angularly selected position on said shaft, whereby the angular position of said pointer at the time of the opening of said switch may be set for any Selected time of day and whereby the pointer may be set to indicate on said dial the correct time of day when the unit is installed.

5. A control unit as defined in claim 4, characterized in that a stop is provided to limit the sliding motion of said shaft in one direction and a spring is provided to hold the shaft yieldably against said stop.

RICHARD A. HAIGH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,926,652 Rosenfeld Sept. 12, 1933 2,224,593 Brown et al Dec. 10, 1940 2,346,694 Maris Apr. 18, 1944

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